Archaeological monitoring took place at the Colchester Garrison Officers’ Club during the excavation of eight foundation-pits (each measuring c.1.0 x 1.0m in area x 1.0 - 1.2m in depth) for floodlights around the perimeter of the new tennis courts. <1> The tennis courts are situated within the Abbey of St John (SAM no 26307; NHLE no 1015015) on the site of the abbey church, which was discovered during an archaeological evaluation in February 2011 (CAT report 601). <2> The robbed-out remains of the southern-most foundation of the abbey church were uncovered in one of the foundation-pits. Combined with the absence of similar remains in the adjacent foundation-pit, this discovery has significant ramifications for the reconstructed plan of the abbey church. A deep deposit of dark soil was encountered in the two foundation-pits to the south-east of the abbey church. The presence of a human skull in one of the pits indicates that, at some time during the life of the church, this area was used for human burial. To the north of the abbey church, human remains were identified immediately south of a mortared rubble-wall (in FP7). The rubble-wall is probably the northern edge of an early medieval rubble-lined grave (15 were uncovered in 1972 to the north of the tennis court). The adjacent foundation-pit contained part of a demolished sandy-clay wall (FP8). This could be the remains of a building destroyed during the fire of 1133. The medieval remains uncovered to the north of the abbey church were overlaid by a deep layer of dark soil which may have been deposited here during the largescale earth-moving which followed the 1133 fire. Two pieces of architectural worked stone which may have come from the abbey church were also recovered during the monitoring. Foundation-pit 3 (FP3) Two ?post-medieval pits (F2 and F4) were identified beneath the topsoil (L2) in FP3. F2 had a grey/brown sandy-silt fill which contained mortar, greensand, peg-tile and many oyster shell fragments. F4 had a similar fill to F2, but only contained greensand and Roman tile fragments. Both pits cut a mid-brown sandy-silt (L7) which was similar in composition to L3.